Study of structural and magnetic properties of nanostructured Fe-Co-Ni-Cu alloy processed by mechanical alloying

In this study, microstructural and magnetic evolution of nanostructured (Fe50Co30Ni20)90Cu10 alloy prepared by mechanical alloying are investigated. The structural and magnetic properties have been evaluated by X-ray diffraction (XRD), scanning electron microscopy (SEM) and vibrating sample magnetometer (VSM). The powder morphology shows that for the powders at the final part of milling time, the particle size distribution falls into a narrower range compared to the powders at the initial time. X-ray diffraction results indicate that, with increasing milling time, the peak broadening of the elements become wider. During mechanical alloying process, after 32 h, two low values of crystallite size are happened. The most dissolved of cobalt, nickel and copper elements are occurred after 16 h of milling time. However, at the last part of the milling time, the crystallize size and lattice strain reaches to about 29.12 nm and 0.221 % respectively. The variation of crystallite size enhances magnetization saturation to about 127.26 emu/g and increases coercivity to approximately 82.86 Oe for milling time of 2 and 48 h, respectively. This alloy exhibits much softer magnetic behavior compared to the Fe50Co30Ni20 alloy reported in the recent work [15].